I used to load with a nitro card wad, lubed cushion wad, nitro wad, shot and overshot.
The past 10 years or so I have tried loading only a nitro card wad , loading with wasp nest with a thin wad on top of that, and a couple of other systems i was told " were the best".
I found that it depends on the gun.
My Beretta muzzle loader can be loaded with no issues.
In my Hughes I use a lubed wad with an .0335 wad on top of that after three shots as well as the nitro card
My son's Chance and Sons vintage gun needs a lubed cushion wad or it will be too fouled to load after the third shot.
My buddy uses only a nitro card wad in his double flint shotgun.
Another uses only wasp nest.
I like wasp nest in my Beretta and use a thin overshot wad on top of that unless we are doing a loot of shooting, then I run a lubed wad occasionally .
The pattern is not affected too the point that the charge will not kill a flushed pheasant cleanly, so I do not concern myself with it.

Cat